feat(rust/cbork): Add report_duplicated_key and report_missing_keys functions to the cbork-utils crate

[stanislav-tkach]

Description

• Add report_duplicated_key and report_missing_keys functions to the cbork-utils crate.

Description of Changes

It is rather common pattern in the Decode trait implementation to check for report duplicated keys and check presence of the required ones. For example in CIP-36 decoding and CIP-509 decoding. I'm not sure if cbork-utils is the best place for these functions, but it would be nice to reuse them instead of having several almost identical implementations.

Please confirm the following checks

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream module

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 272/272}$ | ${\color{red}Fail: 0/272}$ |